一款Jenkins的综合漏洞利用工具-JenkinsExploit-GUI

• 前序遍历_迭代法

public List<Integer> preorderTraversal(TreeNode root){
    List<Integer> result = new ArrayList<>();
    if(root == null) return result;
    Deque<TreeNode> stack = new ArrayDeque();
    stack.push(root);
    while(!stack.isEmpty()){
        TreeNode node = stack.pop();
        result.add(node.val);
        if(node.right != null) stack.push(node.right);
        if(node.left != null) stack.push(node.left);
    }
    return result;
}

• 中序遍历_迭代法
• 思路：

1. 将cur一直到树的最左下位置的null，再开始向result加元素。
2. 再依次从stack取元素给cur，用cur.val给res加元素。
3. 再cur = cur.right;//这一句代码很妙

public List<Integer> inorderTraversal(TreeNode root){
    List<Integer> result = new ArrayList<>();
    if(root == null) return reault;
    Deque<TreeNode> stack = new ArrayDeque<>();
    TreeNode cur = root;
    while(cur != null || !stack.isEmpty()){
        while(cur != null){
            stack.push(cur);
            cur = cur.left;
        }
        cur = stack.pop();
        reault.add(cur.val);
        cur = cur.right;
    }
}

• 后序遍历_迭代法

oublic List<Integer> postorderTraversal(TreeNode root){
    List<Integer> result = new ArrayList<>();
    if(root == null) return result;
    Deque<TreeNode> stack = new ArrayDeque<>();
    stack.push(root);
    Deque<Integer> outputStack = new ArrayDeque<>();
    while(!stack.isEmpty()){
        TreeNode node = stack.pop();
        outputStack.push(node.val);
        // 这个左右顺寻保持和result（左-右）一样
        if(node.left != null) stack.push(node.left);
        if(node.right != null) stack.push(node.right);
    }
    while(!outputStack.isEmpty()){
        result.add(outputStack.pop());
    }
    return result;
}

总结：前序、后序的前四行代码完全一样，后序多定义了一个outputStack